var openNew = {
  params : 'top=5,left=5,width=600,height=400,scrollbars=1,resizable=1,location=1,toolbar=1,menubar=1,status=1',
  init : function() {
    if (!document.getElementsByTagName) { return; }
    var theLinks = document.getElementsByTagName('a');
    for (var i=0,allLinks=theLinks.length; i<allLinks; i++) {
      if (theLinks[i].className.match('new_window')) {
         theLinks[i].onclick = openNew.openIt;
         theLinks[i].title = 'This link opens in a new browser window';
      }
    }
  },
  openIt : function() {
    window.open(this.href, '_blank', openNew.params);
    return false;
  }
}
window.onload = openNew.init;